airbag warning light
A common issue with Citroen/Peugeot front seats is if they get pushed/slammed back when adjusting it does dislodge the wiring plug enough to show a fault. However I think all your problems are down to a flat battery. A new/good 12 volt battery has getting on for 13 volts in it so your <10 volts won't cut it. Where I work it's not unusual to have to piggyback two jump packs to start some cars.